Sura Al-Khafaji and  Phil Purnell,  Effect of Coupling Media on Ultrasonic Pulse Velocity in Concrete: A Preliminary Investigation.   journal   = {International Journal of Civil and Environmental Engineering}, [online]. World Academy of Science, Engineering and Technology.
    January 2016, vol. 110(2). 118 - 122
    [viewed 26 April 2024]. Available from: https://publications.waset.org/pdf/10003595.